Synthesis of alpha beta-unsaturated trifluoromethyl ketones from 4-dimethylamino-1,1,1-trifluorobut-3-ene-2-one by addition of Grignard reagents

Enaminones are available by reaction of 4-ethoxy-1,1,1-trifluorobut-3-ene-2 -one with amines such as dimethylamine and they react with Grignard reagent s to give alpha beta-unsaturated trifluoromethyl ketones in good yield by 1 ,4-addition followed by elimination. The generality of this procedure is co ntrasted with reactions based either on the use of organolithium nucleophil es, or the use of 4-alkoxy-alpha beta-unsaturated trifluoromethyl ketones a s electrophilic partners. (C) 2000 Elsevier Science Ltd. All rights reserve d.